I have a 66 Bonneville with a 389. After installing a stock replacement cam and lining up the timing marks, the cam is 180 degrees out. Have the cams changed?
If you lined up the timing marks by having the dot on the cam gear in the 6 o'clock position and the dot on the crank gear in the 12 o'clock position, that puts #6 piston at TDC of it's compression stroke. That's OK as long as you remember that when you run your plug wires. If you leave the crank in the same position, when you stab your dist, you need to turn the housing til the rotor points to the terminal you want to plug #6 plug wire into. If you prefer to start with #1, then you'll have to rotate your crank one full turn (360 degrees). This will put the timing dot on the cam gear in the 12 o'clock position, and the crank gear dot will still be in the 12 o'clock position also. This is because the crank turns exactly two revolutions while the cam is turning only one revolution.So if you stop the crank with both timing dots in the 12 o'clock position, then stab your dist and rotate it til the rotor points to the terminal you want to plug #1 plug wire into. if it will not point to the terminal you want to use for #1, then you can pull the dist back out and turn the rotor til it points to the terminal you do want to be #1, then stab it back in. Keep in mind, that you will probably have to turn the oil pump driveshaft with a long screwdriver, to line it up with the dist shaft so the dist gear will line up with the slot in the oil pump shaft and allow the dist to drop down into position. Some times this takes several small adjustments with the screwdriver.And don't forget, once you have chosen your #1 terminal, the Pontiac rotor turns counterclockwise. So you'll have to connect your plug wires in the proper firing order in a counterclockwise direction. Of course, after you have chosen #1, run #8 next, then #4, #3, #6, #5, #7, #2. That's 18436572 in a counterclockwise direction around the cap. Be careful not to cross #5 and #7 plug wires. It's easy to do !http://boxwrench.net/specs/pont_265-455.htm
helloyour comment makes no sense to me.line up the marks so the crank one is up and the cam one is down and put it together.timing marks have never ever changed.
here's an article by Rocky Rotella that may help clarify things.http://www.highperformancepontiac.com/tech/hppp_0709_pontiac_comp_cams_camshaft_swap/camshaft_installation.html
180 degrees out is normal .When you put the distributor in set it to #1 on the compression stroke .
I'm sorry you didn't understand my comment. I'm from the country and maybe my communication skills are not as good as they should be. I understand PART of your comment. "timing marks have never changed." Now this I understand and agree with totally ! I started building Pontiac motors back in the 1970's, and the timing dots on the cam and crank gears are in exactly the same place they were 40 years ago !"line up the marks so the crank one is up and the cam one is down" This part I also understand. It's easier to make sure the two gears are in proper relationship to one another if you put the two dots together."and put it together" Now there is where you lose me. Exactly what does that mean ? The distributor must be installed in the correct position and the plug wires must be connected to the dist cap in the correct position. So, if this is not done the way I described, then exactly how do you propose it be "put together" ?Click on the link posted above by My71. Then go down that page and click on the picture of the timing set. A larger pic of the timing set will appear and the caption says what I'm saying in a slightly different way. Maybe it will be easier to understand--don't know.
gtojack1366:180 degrees out is normal .When you put the distributor in set it to #1 on the compression stroke ."180 degrees out is normal." Yes, EVERY time the timing dots are together, the #6 piston is at the top of it's compression stroke. So if you want the #1 piston to be at the top of it's compression stroke, instead of #6, then I suppose you could say it's "180 degrees out", since #1 and #6 plug wire terminals on the dist cap are exactly opposite each other or 180 degrees apart.Also to get the #1 piston to TDC of it's compression stroke, you must rotate the cam 1/2 turn which is 180 degrees.So, in a manner of speaking, I suppose you could say that when the timing dots are together, it's "180 degrees out".
hello bigd;my post was directed to the op.sorry, i forgot to put his name on it, lol.